Mobile communication systems where mobile terminals, often termed user equipment, communicate wirelessly have become more and more popular.
Mobile communication systems, such as public land mobile systems are operated by Operators. There may in geographical areas, such as in a country, exist a number of different operators.
At the same time it is today not uncommon that mobile terminals are involved in data communication without user involvement, often referred to as machine-machine communication. A mobile terminal may thus be provided in a machine, such as a car and communicate with other machines via the mobile communication system.
The mobile terminal may in this case also be owned by a company. Such a company may not want the mobile terminal to be too tightly linked to a specific operator, but may want to change operator or at least have the option of such a change of operator.
Various access rights for the mobile terminal to a mobile communication system is often related to a subscription and a subscriber identity, such as an International Mobile Subscriber Identity (IMSI). The handling of such a subscription on behalf of the mobile terminal is then often carried out with the use of a smart card such as a Subscriber Identity Module (SIM) a Universal Integrated Circuit Card (UICC) or an embedded UICC (eUICC).
In order to change from a first mobile communication system to a second mobile communication system the following steps may have to be performed:
1. The smart card downloads, using the radio circuit of the mobile terminal and the access network of the first mobile communication system, a new subscription remotely from a subscription manager
2. The subscription manager sends a mobile terminated SMS (SMS-MT) to the smart card to enable the new subscription
3. The smart card enables the new subscription, disables old subscription, and switches to the subscription
4. The smart card triggers the mobile terminal to reset
5. the mobile terminal resets and
6. the mobile terminal re-connects to the network with the new subscription using a new IMSI.
Steps 3-5 are often termed “Enabling Subscription Process”. As can be seen the mobile terminal has to be reset in order to switch (attach) to the new system. The “Enabling Subscription Process” takes at least 30 seconds to complete with reset of the mobile terminal. Thereafter it takes several seconds to attach to the new mobile communication system with the new subscription. The delay is too long if there is real-time traffic going on with the mobile terminal or if the mobile terminal is not delay-tolerant, and the major reason for the delay is that the mobile terminal needs to reset to switch and attach to the new network.
The delay may for instance be problematic if the mobile terminal is involved in an activity that requires fast communication or if it needs to have the option to issue hazard warnings. Such a delay may thus be unacceptable.
There is therefore a need for an improvement when changing from one subscription to another. There is particularly a need for a change of subscription that is considerable faster than the one described above.